The overall goal of the proposed studies is to examine the role of frontal lobe atrophy in the behavioral and cognitive changes of healthy aging and Alzheimer's disease. The aims of the studies proposed are: 1) to examine whether frontal lobe atrophy is similar or has a distinct pattern in Alzheimer's disease as compared to healthy aging; 2) to determine if frontal lobe atrophy in specific regions of interest (ROI) of the frontal lobe predicts which cognitively intact healthy elderly will subsequently develop Alzheimer's disease; and 3) to determine the relationship between cognitive and social behavioral abilities and frontal lobe volume in healthy elderly and patients with Alzheimer's disease. These studies will be accomplished by calculating and comparing volumetric data on five ROIs from MR scans of healthy aged, Alzheimer's disease patients, and subjects with incipient dementia. Cognitive and behavioral data collected for Aim 3 will be related to ROI volumes to determine the consequences of frontal lobe atrophy on cognitive functioning in healthy aging and Alzheimer's disease.